Delivery of implantable therapeutic devices by less invasive means has been demonstrated to be desirable in numerous clinical situations. For example, vascular embolization has been used to control vascular bleeding, to occlude the blood supply to tumors, to occlude fallopian tubes, and to occlude vascular aneurysms, particularly intracranial aneurysms. In recent years, vascular embolization for the treatment of aneurysms has received much attention. Implants used to treat aneurysms are often convoluted or coiled lengths of wound wire and are referred to as “microcoils.” Microcoils work by filling an aneurysm causing the bloodflow through the aneurysm to slow or stop, thereby inducing thrombosis within the aneurysm.
Microcoils are extremely flexible and have very little structural integrity. In order to make them easier to retrieve and reposition, recent efforts have been directed to making them stretch-resistant. For example, a stretch-resistant embolic coil having a stretch-resistant member passing through the interior lumen of the coil is described in U.S. Pat. No. 5,582,619 to Ken. US Patent Publication No. 2004/0034363 to Wilson also discloses an embolic coil with a stretch resistant member having a distal end attached near the distal end of the coil and a proximal end of the member attached to a delivery catheter.
Several different treatment modalities have been employed in the prior art for deploying implant devices. For example, numerous repositionable detachment systems for implant devices have been described in the prior art including U.S. Pat. No. 5,895,385 to Guglielmi et al. and U.S. Pat. No. 5,108,407 to Geremia et al., the contents of which are hereby incorporated by reference. Several systems, such as those disclosed in U.S. Pat. No. 6,500,149 to Gandhi et al. and U.S. Pat. No. 4,346,712 to Handa et al., the contents of which are hereby incorporated by reference, describe the use of a heater to detach and deploy the implant device.